The fullmoon Uposatha (http://zugangzureinsicht.org/html/ptf/dhamma/sila/uposatha2017.html) marks the Beginning of the 14/15 days "Pchom Pen (http://forum.sangham.net/index.php/topic,8190.0.html)" observing (kan, from khan(dhā), hold, hold up, stick to; pen, or ben, from piṇḍa, pice of rice, alms), till the final big festifal. Starting from this day people in Cambodia would frequent the monasteries to dedicate food for their ancestors and beloved lost family members.